Patient survival in severe low-flow, low-gradient aortic stenosis after aortic valve replacement or conservative management

Novel Techniques and Technologies for Surgical Aortic Valve Replacement: A Large Retrospective Cohort Analysis

Background/Objectives: In an era of growing evidence for transaortic valve implantation (TAVI), our research topic was the evaluation of how surgical aortic valve replacements (SAVRs) are performing in terms of short- and long-term outcomes in different risk categories. Methods: This was a single centre, prospective, and observational cohort study of consecutive patients with aortic valve stenosis, undergoing isolated aortic valve replacement using a biological or mechanical prosthesis, Freestyle™ (Medtronic, Minneapolis, MN, USA) graft, homograft, or Ross procedure. The participant data were collected by review of an internal database. The primary endpoints were all-cause operative mortality (in hospital and at 30 days) and late mortality at the follow-up date. The secondary composite endpoint was the incidence of postoperative complications. Results: 1501 patients underwent SAVR; the mean age was 67 years (SD: 12.6). The in-hospital mortality was 1% (n = 16). At a median follow-up of 60 months, the survival rate was 98.7%. The main predictors for mortality were operative urgency and cardiogenic shock. The overall incidence of PPM was 2.3% (n = 34). Patients who underwent Ross procedure were younger (mean age: 20 years (SD: 1.7)), had a lower incidence of postoperative complications, and were all alive at follow-up. Conclusions: SAVR shows an excellent survival rate and a low rate of postoperative complications despite an increasing surgical risk. Recent advancements in technology, like sutureless/rapid deployment prostheses and minimally invasive techniques, are shown to have favourable effects on outcomes.

Prognostic Impact of High-Molecular-Weight von Willebrand Factor Multimer Ratio in Classical Low-Flow Low-Gradient Aortic Stenosis

INTRODUCTION

High-molecular-weight (HMW) von Willebrand factor (VWF) multimer deficiency occurs in classical low-flow, low-gradient (LF/LG) aortic stenosis (AS) due to shear force-induced proteolysis. The prognostic value of HMW VWF multimer deficiency is unknown. Therefore, we sought to evaluate the impact of HMW VWF multimer deficiency on clinical outcome.

METHODS

In this prospective research study, a total of 83 patients with classical LF/LG AS were included. All patients underwent dobutamine stress echocardiography to distinguish true-severe (TS) from pseudo-severe (PS) classical LF/LG AS. HMW VWF multimer ratio was calculated using densitometric Western blot band quantification. The primary endpoint was all-cause mortality.

RESULTS

Mean age was 79 ± 9 years, and TS classical LF/LG AS was diagnosed in 73% (n = 61) and PS classical LF/LG AS in 27% (n = 22) of all patients. Forty-six patients underwent aortic valve replacement (AVR) and 37 were treated conservatively. During a mean follow-up of 27 ± 17 months, 47 deaths occurred. Major bleeding complications after AVR (10/46; 22%) were more common in patients with HMW VWF multimer ratio <1 (8/17; 47%) in comparison to patients with a normal multimer pattern (2/29; 7%) at baseline (p = 0.003). In a multivariable Cox regression analysis, HMW VWF multimer deficiency was a predictor of all-cause mortality (HR: 3.02 [95% CI: 1.31-6.96], p = 0.009) in the entire cohort. This association was driven by higher mortality rates in the AVR group (multivariable-adjusted HR: 9.4; 95% CI 2.0-43.4, p = 0.004).

CONCLUSIONS

This is the first study to demonstrate the predictive value of HMW VWF multimer ratio for risk stratification in patients with classical LF/LG AS. HMW VWF multimer deficiency was associated with an increased risk of all-cause mortality and major bleeding complications after AVR.

A retrospective study: do patients with left ventricular ejection fraction ≤50% benefit from heart valve surgery?

Background

Left ventricular ejection fraction (LVEF) is an indicator of heart failure, and it is controversial whether patients with reduced preoperative left ventricular ejection fraction can benefit from heart valve surgery. We aimed to assess the differences in clinical characteristics after surgery in patients with different grades of reduced preoperative LVEF to guide clinical management.

Methods

A total of 100 heart valve disease patients with low LVEF (≤50%) who had undergone valve surgery in the Department of Cardiology. The patients were divided into three groups according to their LVEF measured by echocardiography before surgery, with LVEF ≤40% as group A, 40%< LVEF ≤45% as group B, and 45%< LVEF ≤50% as group C. Clinical characteristics such as postoperative LVEF values, oxygenation index, liver function and inflammatory index, intra-aortic balloon pump (IABP) utilization rate, and mortality were compared among the three groups of patients.

Results

There was no statistically significant difference in the preoperative baseline data between the three groups of patients (P>0.05). The clinical outcomes of patients in group A (n=28) were similar to those of patients in groups B (n=39) and C (n=33) (P>0.05). The vasoactive-inotropic score (VIS), postoperative ventilator use time, length of stay in the care unit, IABP use rate, and mortality rate on the first postoperative day were higher in group A. By comparing the preoperative and postoperative (within 48 hours and 3 months after surgery) cardiac echocardiograms of the three groups, we learned that LVEF increased, LV end-systolic internal diameter and LV end-diastolic internal diameter decreased, and ventricular remodeling improved after surgery compared with the preoperative period (P<0.05). The postoperative improvement was more obvious in group A than in groups B and C. Three months after surgery, LVEF increased to 55%, the LV end-systolic internal diameter decreased to 39 mm, and the LV end-diastolic internal diameter decreased to about 55 mm in each group (P>0.05).

Conclusions

Patients with heart valve disease and low LVEF should be actively treated with heart valve surgery, which can significantly improve the patient's left ventricular reverse remodeling and cardiac function, thereby facilitating survival.

Aortic Valve Replacement in the Failing Left Ventricle: Worthwhile?

Purpose

According to the 2020 American College of Cardiology/American Heart Association guidelines, the aortic valve should be replaced in the setting of severe aortic stenosis or regurgitation, independent of left ventricular function (even for EF < 55%). However, in clinical practice, especially in a very low EF range, surgeons may avoid surgical aortic valve replacement (SAVR) because of concern over operative risk. This study examines outcomes of patients with EF ≤ 35% undergoing SAVR.

Methods

From 2004 to 2019, 895 patients underwent SAVR for aortic stenosis (AS) and/or regurgitation (AR) by a single surgeon at our institution. From among these, 40 patients (4.47%) had an ejection fraction (EF) of 35% or less, forming the study group. Intra-aortic balloon pump was placed intraoperatively prophylactically pre-bypass in 18 out of the 40. Preoperative and post-operative echocardiograms were compared to determine changes in ejection fraction. Mid-term survival was assessed.

Results

16 patients presented with AS, 20 with AR, and 4 with a combination of AS and AR. Hospital survival was 97.5% (one patient death). The average ejection fraction progressively improved over time from 26% initially to 46% mid-term with mean follow-up of 43 months (0.1-140.7). Remarkably, five-year survival was comparable between the study group and an age- and gender-matched general population (p = 0.834). Downward trends in LV end-diastolic diameter and end-systolic diameter were seen. The former achieved statistical significance (6.0 cm to 5.3 cm; p = 0.0046), while the latter fell slightly short (4.8 cm to 4.1 cm; p = 0.056). Patients in whom an IABP was used had lower EFs than those without IABP (range 10-35, mean 23% vs. 15-35%, mean 27.6%). The EFs of the three subgroups improved significantly postoperatively (p < 0.001 for AS, p = 0.002 for AR, and p = 0.046 for AS and AR).

Conclusions

Surgical AVR can be done safely in patients with a failing LV with EF ≤ 35%. Significant improvements in the ejection fraction are seen over time. We believe there is a role for prophylactic pre-bypass IABP. Five-year survival is normalized. Surgeons should not hesitate to perform AVR in these highly jeopardized patients.

Impact of Managing Provider Type on Severe Aortic Stenosis Management and Mortality

Background Many patients with symptomatic severe aortic stenosis do not undergo aortic valve replacement (AVR) despite clinical guidelines. This study analyzed the association of managing provider type with cardiac specialist follow-up, AVR, and mortality for patients with newly diagnosed severe aortic stenosis (sAS). Methods and Results We identified adults with newly diagnosed sAS per echocardiography performed between January 2017 and March 2019 using Optum electronic health record data. We then selected from those meeting all eligibility criteria patients managed by a primary care provider (n=1707 [25%]) or cardiac specialist (n=5039 [75%]). We evaluated the association of managing provider type with cardiac specialist follow-up, AVR, and mortality, as well as the independent association of cardiac specialist follow-up and AVR with mortality, within 1 year of echocardiography detecting sAS. A subgroup analysis was limited to patients with symptomatic sAS. Patient characteristics and comorbidities at baseline were used for covariate-adjusted cause-specific and multivariable Cox proportional hazard models assessing group differences in outcomes by managing provider type. An adjusted Cox proportional hazard model with additional time-dependent covariates for follow-up and AVR was used to assess these practices' association with mortality. Within 1 year of echocardiography detecting sAS, data revealed that primary care provider management was associated with lower rates of cardiac specialist follow-up (hazard ratio [HR], 0.47 [95% CI, 0.43-0.50], P<0.0001) and AVR (HR, 0.58 [95% CI, 0.53-0.64], P<0.0001) and with higher 1-year mortality (HR, 1.45 [95% CI, 1.26-1.66], P<0.0001). Cardiac specialist follow-up and AVR were independently associated with lower mortality (follow-up: HR, 0.55 [95% CI, 0.48-0.63], P<0.0001; AVR: HR, 0.70 [95% CI, 0.60-0.83], P<0.0001). Results were similar for patients with symptomatic sAS. All analyses were adjusted for baseline patient characteristics and comorbidities. Conclusions For patients newly diagnosed with sAS, we observed differences in rates of cardiac specialist follow-up and AVR and risk of mortality between primary care provider- versus cardiologist-managed patients with sAS. In addition, a lower likelihood of receiving follow-up and AVR was independently associated with higher mortality.

The role of TAVR in patients with heart failure: do we have the responses to all questions?

Severe aortic stenosis (AS) is the most prevalent valvular heart disease in developed countries. Heart failure (HF) is a frequent comorbidity of this condition and represents a diagnostic and therapeutic challenge. The spectrum of both conditions has become progressively wider in the last decade; HF has been divided in three groups according to left ventricular ejection fraction (LVEF) and severe AS has been reclassified into four groups according to aortic valve (AV) gradient, AV flow measured by LV stroke index, and LVEF. Although all four AS types may be found in patients with signs and symptoms of HF, low-flow AS with low or normal gradient is the most common type in these patients. Several studies have documented that patients with low-flow severe AS have a higher mortality risk than patients with normal-flow and high-gradient AS not only during the natural progression of the disease, but also after either interventional or surgical AV replacement. Existing data support transcatheter AV replacement (TAVR) in patients with severe AS, irrespective of AV gradient, AV flow, and LVEF. Controversial issues, however, are still present on this topic, which has not been adequately addressed by large studies and trials. This clinical review summarizes the epidemiology of the different HF types in patients with severe AS, as well as the impact of HF and LVEF on clinical outcomes of AS patients either untreated or after AV replacement. In particular, we addressed the influence of AV gradient and AV flow on all-cause and cardiovascular mortality in AS patients after TAVR.

Imaging Challenges in Patients with Severe Aortic Stenosis and Heart Failure: Did We Find a Way Out of the Labyrinth?

Aortic stenosis (AS) is the most frequent degenerative valvular disease in developed countries. Its incidence has been constantly rising due to population aging. The diagnosis of AS was considered straightforward for a very long time. High gradients and reduced aortic valve area were considered as "sine qua non" in diagnosis of AS until a growing body of evidence showed that patients with low gradients could also have severe AS with the same or even worse outcome. This completely changed the paradigm of AS diagnosis and involved large numbers of parameters that had never been used in the evaluation of AS severity. Low gradient AS patients may present with heart failure (HF) with preserved or reduced left ventricular ejection fraction (LVEF), associated with changes in cardiac output and flow across the aortic valve. These patients with low-flow low-gradient or paradoxical low-flow low-gradient AS are particularly challenging to diagnose, and cardiac output and flow across the aortic valve have become the most relevant parameters in evaluation of AS, besides gradients and aortic valve area. The introduction of other imaging modalities in the diagnosis of AS significantly improved our knowledge about cardiac mechanics, tissue characterization of myocardium, calcium and inflammation burden of the aortic valve, and their impact on severity, progression and prognosis of AS, not only in symptomatic but also in asymptomatic patients. However, a variety of novel parameters also brought uncertainty regarding the clinical relevance of these indices, as well as the necessity for their validation in everyday practice. The aim of this review is to summarize the prevalence of HF in patients with severe AS and elaborate on the diagnostic challenges and advantages of comprehensive multimodality cardiac imaging to identify the patients that may benefit from surgical or transcatheter aortic valve replacement, as well as parameters that may help during follow-up.

Impact of Surgical and Transcatheter Aortic Valve Replacement in Low-Gradient Aortic Stenosis: A Meta-Analysis

OBJECTIVES

The aim of this study was to assess the impact of aortic valve replacement (AVR) on survival in patients with each subclass of low-gradient (LG) aortic stenosis (AS) and to compare outcomes following surgical AVR (SAVR) and transcatheter AVR (TAVR).

BACKGROUND

LG severe AS encompasses a wide variety of pathophysiology, including classical low-flow, LG (LF-LG), paradoxical LF-LG, and normal-flow, LG (NF-LG) AS, and uncertainty exists regarding the impact of AVR on each subclass of LG AS.

METHODS

PubMed and Embase were queried through October 2020 to identify studies comparing survival with different management strategies (SAVR, TAVR, and conservative) in patients with LG AS. Pairwise meta-analysis comparing AVR versus conservative management and network meta-analysis comparing SAVR versus TAVR versus conservative management were performed.

RESULTS

Thirty-two studies with a total of 6,515 patients and a median follow-up time of 24.2 months (interquartile range: 36.5 months) were included. AVR was associated with a significant decrease in all-cause mortality in classical LF-LG (hazard ratio [HR]: 0.42; 95% confidence interval [CI]: 0.36 to 0.48), paradoxical LF-LG (HR: 0.41; 95% CI: 0.29 to 0.57), and NF-LG (HR: 0.41; 95% CI: 0.27 to 0.62) AS compared with conservative management. SAVR and TAVR were each associated with a decrease in all-cause mortality in classical LF-LG (HR: 0.46 [95% CI: 0.38 to 0.55] and 0.49 [95% CI: 0.37 to 0.64], respectively), paradoxical LF-LG (HR: 0.42 [95% CI: 0.28 to 0.65] and 0.42 [95% CI: 0.25 to 0.72], respectively), and NF-LG (HR: 0.40 [95% CI: 0.21 to 0.77] and 0.46 [95% CI: 0.26 to 0.84], respectively) AS compared with conservative management. No significant difference was observed between SAVR and TAVR.

CONCLUSIONS

In all subclasses of LG AS, AVR was associated with a significant decrease in all-cause mortality regardless of surgical or transcatheter approach.

Patient survival in severe low-flow, low-gradient aortic stenosis after aortic valve replacement or conservative management

BACKGROUND AND AIM

Classical and paradoxical low-flow, low-gradient (LFLG) aortic stenosis (AS) are the most challenging subtypes of AS. The current therapeutic options are aortic valve replacement (AVR) and conservative management: AVR promotes long-term survival but is invasive, while conservative management yields a poor prognosis but is noninvasive since it uses no aortic valve replacement (noAVR). The present meta-analysis investigated the rate of survival of patients with LFLG AS undergoing either AVR or noAVR interventions.

METHODS

The meta-analysis compared the outcomes of AVR with those of noAVR in terms of patient survival. In both groups, a meta-regression was conducted to investigate the impact on patient survival of the left ventricular ejection fraction (LVEF), either preserved (paradoxical LFLG AS) or reduced (classical LFLG AS).

RESULTS

The relative risk of survival between the AVR and noAVR groups was 1.99 [1.40, 2.82] (p = .0001), suggesting that survival tends to be better in AVR patients than in noAVR patients. The meta-regression revealed that a reduced LVEF may be related to a higher survival in AVR patients when compared to a preserved LVEF (p = .04). Finally, the analysis indicated that LVEF seems not to be prognostic of survival in noAVR patients (p = .18).

CONCLUSIONS

Patients with LFLG AS have better survival if they undergo AVR. In AVR patients, reduced LVEF rather than preserved LVEF is related to better survival, whereas there seems to be no difference in prognostic value between reduced and preserved LVEF in noAVR patients.